Is that the only change or are they doing this on more routes?
The solutions are simple: Either use a combination of tickets, or go via London.
Let's say you want to leave Manchester at 0830.
Manchester to Bournemouth SVR £102.90 (Not London)
Manchester to Crewe* SOR £14.60
Crewe* to Birmingham SVR £22.10 (Valid after 0900

)
Birmingham to Banbury SVR £16.50 (Valid after 0930)
Banbury to Reading SVR £20.50 (Valid after 0930)
Reading to Bournemouth SVR £33.75 (Valid after 0930)
TOTAL = £107.45
Only a fiver more than the through off peak, yet you can leave Manchester at any time and leave Crewe after 9am. For 20 quid more you can leave Crewe at any time and Birmingham after 9.30am. And so on...
And the best bit? Under ORCATS XC get even less money, and you give more money to Chiltern, Northern, FGW, etc
And in the other direction the solution is REALLY easy. Simply get a +London ticket for only £1.50 extra. This is valid by any train from Bournmouth to London, and then is only restricted out of Euston (can be used after 0926 from Euston, that is far better than leaving Bournemouth at 0930), and XC will get only a tiny amount of your cash.
* Or take Virgin to Stoke (£11.00 SOR), and then 2 x SDS from Stoke to Birmingham or, if it's now after 0930, get an SVR from there. Or, for early birds on the 0627 from Manchester, get another SOR on Virgin for £11.00 Stoke to Birmingham.
Many other combinations exist.
Also, a Chorley to Bournemouth is £111.50 and is priced by Virgin and valid after 0415.
Anyone who uses this site or is vaguely aware of split ticketing need not get caught out!